Researchers at São Paulo State University’s Chemistry Institute (IQ-UNESP) in Araraquara, Brazil, working with colleagues at Oxford University in the UK have developed a technological platform that could result in the creation of ultrasensitive biosensors for rapid early diagnosis of several diseases, including breast and prostate cancer, Parkinson’s and Alzheimer’s.
Organized by the Montevideo Group Association of Universities (AUGM), Uruguay’s University of the Republic (UDELAR) and FAPESP, the symposium took place on November 17-18 at UDELAR’s campus in Montevideo. Its purpose was to strengthen existing collaborations and establish new partnerships among South American scientists in a range of knowledge areas. Researchers and leaders of institutions in Uruguay, Brazil, Argentina, Chile and Paraguay attended the meeting.
“The technological platform we’ve developed is so sensitive that it can be used to detect prostate cancer, for example, at a very early stage when few cancer cells are in the bloodstream and diagnosis by biopsy would be impossible”, said Paulo Roberto Bueno, a professor at UNESP Araraquara and principal investigator for the project, in an interview given to Agência FAPESP.
The method consists of detecting and measuring specific antibodies, proteins or other biomarkers (biological characteristics that are evaluated as indicators of the state of a disease or the response to a drug) in a blood sample or other biological material using microscopic electrodes.
When a biological molecule such as an antibody that serves as a biomarker of a specific disease is immobilized on the surface of a microelectrode designed at the molecular level, it is possible to detect the presence of its antigen in a blood sample using the quantum capacitance method.
When the antigen in a patient’s blood sample comes into contact with the antibody immobilized on the microelectrode, it changes the capacitive electric signal or charge of the surface material in a highly sensitive manner.
This change in the electric signal is measured to determine in minutes the presence of an antigen in the solution and quantify it specifically without interference from other proteins in the blood matrix.
“This process enables us to create an ultra-sensitive and highly selective system for detecting biological molecules of clinical interest in a blood sample, for example,” Bueno said.
In order to identify only one type of molecule among the thousands present in a patient’s blood sample, which can also affect the electric signal, the system performs a spectroscopic analysis of their capacitance spectra.
To this end, the method proposed by Bueno’s research group compares a standard blood sample that lacks the given antibody (used as a reference electric signal) with the sample analyzed.
Any electric signal that differs from the reference signal can be identified and quantified by the method, Bueno explained.
“The technology can also combine several electrodes to detect the presence of several biomarkers, such as those associated with prostate cancer, and quantify them simultaneously,” he said.
The most widely used biomarker for prostate cancer is prostate-specific antigen (PSA), which at high levels may indicate the development of this disease, the cancer that causes the most male deaths in Brazil after lung cancer. However, PSA levels can vary naturally.
To determine a patient’s risk of developing prostate cancer more accurately, the method can detect other biomarkers at the same time, such as total PSA and prostatic acid phosphatase (PAP).
“If the system detects that these three biomarkers are all significantly and constantly altered in a patient, the physician may identify a risk of prostate cancer and refer the patient for preventive treatment, for example,” Bueno said.
“The same goes for other diseases that should be diagnosed early if possible, such as Parkinson’s and Alzheimer’s.”
Instead of taking a blood sample from a patient with suspected dengue or Zika infection and sending it to a laboratory for analysis, which can take weeks, the method could be used for analysis of the sample in the patient’s own home by health workers. The results of the analysis could be sent via the internet to a local hospital where the patient would be sent for treatment.
“In addition to rapid diagnosis, the method offers the possibility of mapping outbreaks of diseases and alerting the health system by creating an intelligent database, which could result in the development of a nationwide online surveillance system that could be updated every day,” Bueno said.
To leverage the platform’s market potential, Oxford University has set up a spinoff called Oxford Impedance Diagnostics (OID), which has licensed three of the five patents and plans to commercialize the technology.
Oxford University’s own investment fund and other angel investors have given OID £2 m in seed money.
“The firm’s business model foresees that within eight years a number of quick tests will be created and internationally commercialized to detect a range of diseases on the basis of the technology platform we’re developing,” Bueno said.